The present invention is generally directed to load carrying or material handling vehicles, such as trucks, trailers, vans, railroad cars and the like. More particularly, the present invention is directed to a trailer including a vertically adjustable roof which can be raised to extra-load the cargo, and then lowered to its initial position.
The prior art is replete with various types of load carrying or material handling trailers or vehicles. Various examples of such load carrying vehicles are disclosed in U.S. Pat. Nos. 2,656,216; 2,797,124; 2,821,428; 3,140,116; 3,319,994; 3,694,024; 4,095,838; 4,206,943; 4,703,971 and 4,544,196. However, although these vehicles generally may include devices for raising and lowering the roofs thereof, they are not directed to compressing the freight without damaging it, to thereby substantially increase the cargo hauling potential. The flexible and/or resilient freight material, such as tires, generally is not damaged if compressed together during transport.
In transporting certain flexible and/or resilient or other types of freight, for example, tires, it has been observed that the freight generally has a tendency to settle several inches, and in some instances two feet or more, below the roof level in a conventional trailer, during transit. Therefore, substantial amount of space is unused and, therefore, wasted. For example, a typical truck-load of tires weighs about 30,000-35,000 lbs., and generally the overall weight limit for the tractor-trailer together with the freight is about 80,000 lbs. However, by compressing the tires together, an higher freight-load of about 45,000-50,000 lbs., may be hauled by the same tractor-trailer, thereby increasing its load carrying capacity.
Accordingly, there is a need for a material carrying or handling vehicle which is capable of transporting greater freight per load than that is which currently hauled by conventional vehicles of this type.